I have observed an interesting phenomena with my vision lately. I just think I have never reflected over this before but it might always have been this way.
I am nearsighted and have no problem with double vision as long as an object is in focus, either with or without glasses.
However when I take my glasses off and look at, e.g. my phone screen, and push it slowly just out of focus, there is a phase where multiple distorted weak ghost images appear before everything just becomes a more Gaussian like blur. It is especially clear with bright lines on a dark surface.
I do not believe that there is anything else wrong with my eyes, since as soon as an object is in a range where I can focus on it, all ghosting disappears.
I am interested in knowing if anyone else observes this.
But more interesting is what are the possible optical properties of the eye that contributes to this, or is it a property of how our brain processes the input from the eyes.